Conventional articles of athletic footwear have included two primary elements, namely, an upper member and a sole member structure. The upper member provides at least a partial covering for the foot that securely receives and positions the foot with respect to the sole structure. In addition, the upper member may have structures and a configuration that protect the foot and provide ventilation, thereby cooling the foot and removing perspiration. The sole structure generally is secured to a lower portion of the upper member and generally is positioned between the foot and the ground. In addition to attenuating ground reaction forces, the sole structure may provide traction and help control foot motions, such as pronation. Accordingly, the upper member and the sole structure operate cooperatively to provide a comfortable structure that is suited for a variety of ambulatory activities, such as walking and running.
The sole member or structure of athletic footwear generally has exhibited a layered configuration that includes a comfort-enhancing insole, a resilient midsole (e.g., formed from a polymer foam material), and a ground-contacting outsole that provides both abrasion-resistance and traction. The midsole typically is the primary sole structure element that attenuates ground reaction forces and controls foot motions. Suitable polymer foam materials for the midsole include ethylvinylacetate or polyurethane that compress resiliently under an applied load to attenuate ground reaction forces. Conventional polymer foam materials are resiliently compressible, in part, due to the inclusion of a plurality of open or closed cells that define an inner volume substantially displaced by gas.
As noted above, various ground reaction force attenuating elements and systems have been known, including such elements and systems for use in footwear products including athletic footwear products. Conventionally, the structure, feel, and characteristics of such elements and systems are selected by a footwear manufacturer, and these elements and systems (as well as their associated characteristics) are permanently fixed in the footwear products once the footwear products are made. Each individual footwear user, however, possesses unique characteristics that affect their physical fitness or training regimes, such as weight, foot size, type of workout or exercise performed, stride or gait characteristics (e.g., a pronation or supination tendency), personal tastes and preferences, etc. Therefore, this “one size fits all” approach to footwear design and production can lead to uncomfortable fits and/or limited sales due to the failure of the footwear products to match the conditions or characteristics desired and/or preferred by users.
Further, manufacturers invest significant amounts of time and money in testing various components of an article of footwear. This testing helps manufacturers to produce the most valuable products that are desired by the widest range of consumers for the products. For example, manufacturers often test various new ideas for products by performing mechanical and reliability testing that provides the manufacturer with valuable information. Additionally, manufacturers may also want to receive feedback from human testers who wear the footwear during certain activities, such as athletic activities (e.g., running, jogging, and other ambulatory activities).
Manufacturers researchers find that the quality of the feedback from human testers varies significantly, which makes the value of such feedback limited. The feedback from human testers is difficult to regulate because many of the human testers are not trained and/or the testers base their feedback on subjective criteria, such as preference for the product, appearance of the product, a pre-conceived expectation of the product, and other subjective criteria. The feedback that the manufacturer or researcher most desires is objective, analytical feedback relating to performance of the product. Many human testers find it difficult to distinguish between objective and subjective feedback. If a manufacturer or researcher is able to obtain objective, analytical feedback of products, such feedback would improve the manufacturer's ability to develop higher quality products and develop products that better match the consumers' needs and wants.
Accordingly, it would be useful to provide footwear products or other foot-receiving devices that are readily customizable to a user's tastes and specifications, e.g., based on the user's individualized needs and/or the characteristics he/she desires in the footwear product or other foot-receiving device in general and/or at a given time. Further, it would be useful to provide methods of testing various components of a footwear product or other foot-receiving device to obtain objective, analytical feedback about a product. Even further, it would be useful to provide methods of training human testers to provide researchers or manufacturers of products with objective, analytical feedback for a product to improve the researchers' or manufacturers' ability to make better products and meet consumers' needs and wants for such products.